In a vehicle powered by a diesel or a direct injection-type internal combustion engine, a particulate filter is positioned within the exhaust stream to capture microscopic particles of soot, ash, sulfates, metallic particles, and/or any other matter. Filter regeneration occurs when the temperature of the exhaust gas passing through the filter is temporarily elevated above a threshold of at least approximately 450 degrees Celsius. The exhaust stream may be further cleansed using a selective catalytic reduction device, which is specially designed to convert nitrogen oxides or NOx gasses into water and nitrogen as additional inert byproducts.